Record: 1375 kmThe Karakum Canal (Qaraqum Canal, Kara Kum Canal, Garagum Canal; Russian: Каракумский канал, Karakumskiy Kanal, Turkmen: Garagum kanaly, گَرَگوُم كَنَلیٛ, Гарагум каналы) in Turkmenistan is one of the largest irrigation and water supply canals in the world. Started in 1954, and completed in 1988, it is navigable over much of its 1,375-kilometre (854 mi) length, and carries 13 cubic kilometres (3.1 cu mi) of water annually from the Amu-Darya River across the Karakum Desert in Turkmenistan. The canal opened up huge new tracts of land to agriculture, especially to cotton monoculture heavily promoted by the Soviet Union, and supplying Ashgabat with a major source of water. The canal is also a major factor leading to the Aral Sea environmental disaster. The Soviet regime planned to at some time extend the canal to the Caspian Sea.